. >> a college student arrested in pennsylvania for possessing a weapon of mass destruction used to call the bay area home. a marijuana operation led to bomb making materials. he planned to blow things up and bought the materials on line. he was arrested for other offenses. the 19-year-old is a student at penn state. he grew up on the peninsula in belmont. >> never thought something like that would happen. >> reporter: he used to be friends with vlad. . >> he was always a bright student and had good grade and a high gpa. he wanted to be an engineer and wanted to graduate from a university and get a good degree. >> other kids remember vlad as being a skater, a quiet kid who hang out with a quiet crowd. he made explosives in california. an old friend he was always into that stuff. but another said he talked about making robots. >> i don't think he is linked to terrorism or doing something to the public. maybe it is a hobby he had. i feel bad for him. i know he wasn't -- it's not something he would do. i guess it was a dumb mistake. >> reporter: his address turned up here and a man wouldn't